Computers with suspend functions have been used that halt the supply of power to some components of internal hardware, and thereby saving power consumption. Under a suspend state, power supplied to a non-volatile memory such as a Hard Disk Drive (HDD) and a Central Processing Unit (CPU) are halted while maintaining a power supplied to a volatile memory such as a Random Access Memory (RAM) to retain stored contents. As described above, the stored contents are retained in the volatile memory. Therefore, swapping in basic programs such as an Operating System (OS), application programs and various data from the non-volatile memory to the volatile memory is not needed when a computer is resumed from the suspend state. Accordingly, the computer reproduces a state immediately before transitioning to the suspend state at a high speed.
The CPU in the above-described computer reads and executes a Basic Input/Output System (BIOS) stored, for example, in a Read-Only Memory (ROM) of a non-volatile memory. The CPU recovers states of respective internal hardware components other than the RAM to the states before transitioning to the suspend state according to the BIOS and starts the OS stored in the RAM. The CPU resumes execution of application programs, for example, that are stored in the RAM after starting the OS and reproduces the state of the CPU before transitioning to the suspend state.
There is a case in which a plurality of operating systems are stored in a HDD, etc. that is included in a computer and an OS to be started up by the CPU that may be manually selected from the plurality of operating systems. When a suspend function is provided to the above-described computer that stores a plurality of operating systems, there is a case in which an OS to be started up is selected when resuming from the suspend state (for example, Japanese Laid-open Patent Publication Nos. 11-288366, 2003-196096, 2000-330806, 2001-256066, and 2009-134595).